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Titration for NaOH (Sodium Hydroxide)
Step 1: Make Reference Tester Solution:
First, make a .1% NaOH in water solution- 1 gram of catalyst in 1
liter of distilled water. Try and be as accurate as possible with the
measurement of the 1 gram of NaOH. Keep it sealed and it'll last for
many titrations. You should be as accurate as possible when measuring
the 1 gram of NaOH. You can improve your accuracy by measuring 3 grams
of NaOH and adding it to three liters of distilled water, or some
similar variation on that theme. Every 1 ml of this solution will now
contain 1/1000 of a gram of NaOH- an amount too small to weigh. The
water makes it possible to measure such tiny amounts of NaOH however.
Keep this base solution in a bottle with a tightly closed lid, make new
base solution every 30 days and make a new base solution each time you
open a new bag of NaOH or KOH.
Step 2-
Perform a blank Titration:
Sometimes alcohol
becomes slightly acidic with age, which would throw off your results. So
we test it by performing a blank titration periodically. A blank
titration looks just like a regular titration but without the oil. A
blank titration neutralizes any acids that the isopropyl contained, so
you're starting with a 'blank' slate and your real titration only reads
the free fatty acids instead of the acids in the isopropyl.
- Add 10 ml of isopropyl
to a small 'beaker' - Add four drops of phenolphthalein or
phenol red' - Swirl. It'll be some sort of yellow color' - Next, add NaOH/water drop by drop and keep swirling' - The
moment it turns purple, stop- you've neutralized all the acids in the
isopropyl. This is your starting point. You will now add oil to the
mixture for the actual 'titration' step. If the isopropyl only
needed 5 or 10 drops of NaOH/water solution to neutralize the acids, it's
not very acidic. If it required a half milliliter or more of NaOH/water
then that's more unusual (you should consider replacing your isopropyl
alcohol). Perform a blank titration every time (it
provides a more neutral starting point for the real titration) and the
chance of batch failure will be greatly reduced.
Step 3:
Measuring Oil Sample:
Measure an exact
1 ml of oil with an oral syringe. Measure the oil with a different
syringe than the isopropyl. The amount of oil is very crucial , but the
isopropyl isn't. Add the 1 ml of oil to the 10 ml of alcohol that you
have prepared above and stir. The liquid will be yellow after you've
added the oil.
Step 4: Add
And Measure NaOH/Water
Base Solution:
Now, add to this
'beaker', a small amount (¼ milliliter at a time) of the
0.1% NaOH solution drop by drop to the
oil-alcohol-phenolphthalein mixture, stirring all the time. It
might turn a bit cloudy, keep stirring. Keep on carefully adding
the NaOH solution until the mixture starts to turn pink (magenta) and
stays that way
for 30 seconds of swirling. Don't mix up your oil and your lye/water
syringes (clean them with isopropyl if you've made a mistake)
(Chopsticks
make the best stirrers for titration.)
Take the number of milliliters of 0.1% NaOH solution you used and add
5 (the basic amount of NaOH needed for waste oil). This is the
total number of grams of NaOH you'll need per liter of the oil you titrated.
Titration for KOH (Potassium Hydroxide)
Step 1: Make Reference Tester Solution:
First, make a .1% KOH in water solution- 1 gram of catalyst in 1
liter of distilled water. Try and be as accurate as possible with the
measurement of the 1 gram of KOH. Keep it sealed and it'll last for many
titrations. You should be as accurate as possible when measuring the 1
gram of KOH. You can improve your accuracy by measuring 3 grams of KOH
and adding it to three liters of distilled water, or some similar
variation on that theme. Every 1 ml of this solution will now contain
1/1000 of a gram of KOH- an amount too small to weigh. The water makes
it possible to measure such tiny amounts of KOH however. Keep this
base solution in a bottle with a tightly closed lid, make new base
solution every 30 days and make a new base solution each time you open a
new bag of NaOH or KOH.
Step 2-
Perform a blank Titration:
Sometimes alcohol
becomes slightly acidic with age, which would throw off your results. So
we test it by performing a blank titration periodically. A blank
titration looks just like a regular titration but without the oil. A
blank titration neutralizes any acids that the isopropyl contained, so
you're starting with a 'blank' slate and your real titration only reads
the free fatty acids instead of the acids in the isopropyl.
- Add 10 ml of isopropyl
to a small 'beaker' - Add four drops of phenolphthalein or
phenol red' - Swirl. It'll be some sort of yellow color'
- Next, add KOH/water drop by drop and keep swirling' - The
moment it turns purple, stop- you've neutralized all the acids in the
isopropyl. This is your starting point. You will now add oil to the
mixture for the actual 'titration' step. If the isopropyl only
needed 5 or 10 drops of KOH/water solution to neutralize the acids, it's
not very acidic. If it required a half milliliter or more of KOH/water
then that's more unusual (you should consider replacing your isopropyl
alcohol). Perform a blank titration every time (it
provides a more neutral starting point for the real titration) and the
chance of batch failure will be greatly reduced.
Step 3:
Measuring Oil Sample:
Measure an exact
1 ml of oil with an oral syringe. Measure the oil with a different
syringe than the isopropyl. The amount of oil is very crucial , but the
isopropyl isn't. Add the 1 ml of oil to the 10 ml of alcohol that you
have prepared above and stir. The liquid will be yellow after you've
added the oil.
Step 4: Add
And Measure KOH/Water
Base Solution:
Now, add to this
'beaker', a small amount (¼ milliliter at a time) of the
0.1%
KOH
solution drop by drop to the oil-alcohol-phenolphthalein mixture,
stirring all the time. It might turn a bit cloudy, keep stirring.
Keep on carefully adding the
KOH
solution until the mixture starts to turn
pink (magenta) and stays that way
for 30 seconds of swirling. Don't mix up your oil and your lye/water
syringes (clean them with isopropyl if you've made a mistake)
(Chopsticks
make the best stirrers for titration.)
Take the number of milliliters’ of 0.1% KOH solution you used and add
7 - 8 (the basic amount of KOH needed for waste oil). This is the
total number of grams of KOH you'll need per liter of the oil you titrated.
To confuse matters
further, KOH comes in a variety of purities. You want an 85% or higher.
However for beginners we recommend just buying the 99% pure. Later on
you can adjust your KOH levels to compensate for impurities (ie if
you've got 90% pure KOH use 10% more of it and so on). Do not adjust the
results of the titration! the titration will automatically reflect the
impurity level for you.
55
US gallons = 208.186 liters
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